Rocker link lift system

ABSTRACT

A lift system for an implement has the lift cylinder near the implement front end. A rocker link with three vertically spaced pivot holes is located rearward of the cylinder and connected to an implement frame by a pivot pin through the center one of the holes. The lift cylinder is connected to the lower pivot hole while two further links are connected to the top hole and extend longitudinally away from one another to control raising and lowering of front and rear wheels respectively. As the cylinder extends and retracts, the rocker pivots causing the front and rear wheels to raise and lower in synchronism with each other. Fore and aft leveling adjustment may be achieved by including a turnbuckle in one of the further links to vary the length thereof relative to the other.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a non-provisional application based upon U.S. provisional patentapplication Ser. No. 61/903,429, entitled “ROCKER LINK LIFT SYSTEM”,filed Nov. 13, 2013, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to agricultural implements, and, moreparticularly, to agricultural field tillage implements.

2. Description of the Related Art

It is not an uncommon sight to see a farm tractor pulling cultivating orplanting implements along rural roads. Field cultivating implements suchas harrows include, in addition to the actual soil working tools such asharrow tines or discs, a set of wheels which are deployed when moving animplement between storage locations and one or more work locationseliminating the need for a separate implement transporting trailer. Thissame set of wheels may be employed to engage the farm field surface andcontrol the depth or penetration of the soil working tools into theearth. A fixed wheel location would probably result in tool and/orroadway damage. Thus, various schemes for retracting and extending thewheels relative to the implement have been suggested. These schemesallow full wheel extension when transporting the implement and acontrollable limited extension when cultivating. The wheels allow theimplement to more nearly follow field contours. These schemes have theadditional advantage that the depth of working tool penetration into thesoil may be controlled for preferred tillage.

The known wheel retracting techniques employ one or more lift cylinderstypically located at or near the rear of the implement, with mechanicallinkages from the cylinders to respective wheels. Their weightundesirably adds weight to the implement behind the wheel pivotsdetrimentally affecting tongue weight.

What is needed in the art is a simple, fully adjustable wheel retractingscheme which shifts the weight forward on the implement.

SUMMARY OF THE INVENTION

The present invention provides improved weight distribution in a fullyadjustable agricultural implement wheel retracting arrangement.

The invention in one form is directed to an agricultural tillageimplement, having a main frame section including a plurality ofgenerally downwardly depending soil working tools. The frame section isadapted to be coupled by a floating hitch arrangement to and towed by atraction unit in a generally horizontal forward direction of travel.There is a first plurality of lift wheels pivotably depending from theframe section, and a second plurality of gauge wheels pivotablydepending from the frame section generally forward of the lift wheels. Alinkage assembly simultaneously pivots certain gauge and lift wheelsbetween respective retracted and extended positions for selectivelylowering and raising the main frame section and associated soil workingtools. The linkage assembly has an actuator pivotably fixed to the mainframe section along with a rocker link pivotably fixed to the main framesection having first and second arms extending therefrom, the first ofwhich is coupled to the actuator. A rearwardly extending lift wheelactuating link is pivotably fixed to the rocker link second arm near oneend and coupled to a lift wheel near another end. A forwardly extendinggauge wheel actuating link is also pivotably fixed to the rocker linksecond arm near one end and coupled to a gauge wheel near another end.One of the actuating links is adjustable in length. The actuator isfixed to the frame reward of the gauge wheels and forward of the rockerlink.

The invention in another form is directed to a linkage assembly for usewith an agricultural implement which is adapted to simultaneously pivotcertain front and rear wheels between respective retracted and extendedpositions for selectively lowering and raising the implement frame andany associated soil working tools. The linkage assembly has an actuatorand a rocker link both pivotably fixed to the implement frame. Therocker link has a first arm extending therefrom coupled to the actuator,and a second arm extending therefrom coupled to a rearwardly extendingwheel actuating link which is in turn coupled to a rear wheel nearanother end. A forwardly extending wheel actuating link is alsopivotably fixed to the rocker link second arm near one end and coupledto a front wheel near another end. The actuator may be a linearhydraulic actuator operable between extended and retracted positionswhich extends from the frame to the rocker link first arm.

An advantage of the present invention is that the implement center ofgravity is shifted forward as compared to typical designs.

Another advantage is full lateral as well as longitudinal levelingfeatures may be incorporated.

Yet another advantage is simplicity of design.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is an isometric view of a portion of an agricultural tillageimplement incorporating the invention in one form showing wheels in aretracted position;

FIG. 2 is an isometric view of the portion of the agricultural tillageimplement of FIG. 1, but showing the wheels in a lowered position;

FIG. 3 is an isometric view of the wheel lift linkage assembly portionof FIG. 2 from a different perspective; and

FIG. 4 is an isometric view of a portion of an agricultural tillageimplement incorporating the invention in another form.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate embodiments of the invention and such exemplifications arenot to be construed as limiting the scope of the invention in anymanner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there isshown a portion of an agricultural tillage implement 10 which generallyincludes a main frame section 12 and, depending therefrom, an array ofdownwardly extending soil working tools such as the harrow tines 14, 16and 18, a set of rear lift wheels 20 and 22, and a front gauge wheel 24.Gauge wheel 24 may be a castor type wheel having a vertical axis ofrotation 76 in some embodiments. The frame section 12 is adapted to becoupled by a conventional floating hitch arrangement (not shown) andtowed by a traction unit in a generally horizontal forward direction oftravel indicated by the arrow 26 (FIGS. 2 and 3).

Referring to the drawings generally, the rear wheels 20 and 22,frequently called lift wheels, depend from the frame 12 on an arm 28which is pivotably fixed to the bracket 30 by knuckle 32. Bracket 30 isrigidly fixed to the implement main frame section 12. A rear lift wheellink 34 is similarly pivotably fixed to the knuckle 32 so thattranslation of link 34 serves to raise and lower the wheels 20 and 22.Thus, if link 34 moves generally leftward as viewed, knuckle 32 pivotscounter-clockwise within the bracket 30 raising the wheels from theposition illustrated in FIGS. 2 and 3 to the position shown in FIG. 1.

Translation of link 34 is achieved by extending or retracting anactuator or lift cylinder 36. The actuator 36 may comprise a linearlyextendable and retractable piston within a hydraulic cylinder and ispivotably fixed to the main frame section 12 by rigid bracket 38.Located rearwardly thereof is a somewhat similar rigid bracket 40 whichpivotably supports a rocker link 42. This rocker link may be moreclearly seen in FIG. 3 and includes three spaced apart apertures thecentral one of which is affixed by a pivot pin 44 to bracket 40. Therocker link 42 includes a downwardly depending or lower arm 48. The holenear the lower end of rocker link arm 48 is pivotably fixed to the lowerend of the actuator 36 while an upper arm 50 of rocker link 42 has theupper end hole which pivotably engages the rear wheel link 34 at pivotpin 46. Thus, when the lift cylinder 36 is extended, rocker arm 50pivots about pin 44 in a clockwise sense as viewed, drawing arm 34generally to the right and lowering wheels 20 and 22, compare FIGS. 1and 2.

Pivot pin 46 defines a common pivot axis which is shared by the rockerlink upper arm 50, the rearwardly extending lift wheel link 34 and aforwardly extending gauge wheel actuating link 52. Link 52 is pivotablycoupled to the gauge wheel 24 by a knuckle 54. The knuckle 54 has apivot axis defined by pin 56 which is fixed relative to the frame 12. Asecond pivot pin 58 defining pivot axis 82 is displaced from pin 56 andreceives the actuating link 52. An arm 60 extends from the knuckle 54 towheel 24.

Front-to-rear leveling of the implement may be achieved by adjusting thelength of the forward wheel actuating link 52 relative to the length oflink 34 by including an adjustable length turnbuckle 62. By including asimilar adjustable lug in the lift cylinder coupling, left-to rightleveling may be achieved. Independent control of lift cylinders such as36 and 64 may also be employed in achieving left-to-right implementleveling.

It will be appreciated that only a portion of the implement (the leftfront as viewed from above and behind in FIGS. 1 and 2) is shown, andthat an essentially mirror image of the portion shown will be present onthe opposite side of the implement, fragments of which are visible inFIG. 3, and that further similar intermediate wheels and linkageassemblies may be present in some applications. For example, FIG. 3shows another lift cylinder 64 analogous to cylinder 36, and anotherturnbuckle 66 in the forward gauge wheel link 68. Also visible in FIG. 3are a rear lift wheel link 70, front wheel arm 72, rocker link 74 andfront knuckle 78. Knuckle 78 receives pins defining a first fixed pivotaxis 80 analogous to the axis defined by pin 56 and a second actuatinglink pivot axis 84 displaced therefrom and analogous to axis 82, alloperating as previously described.

FIG. 4 illustrates another embodiment of the invention viewed in adifferent orientation. Here, the right front gauge wheel 86 along withrear lift wheels 88 and 90 are visible as viewed from the front of theimplement. Implement frame 92 supports the linkage assembly 94. Thelinkage assembly includes hydraulic actuator 96 and rocker link 98 whichis pivotably fixed to the frame 92 by the rigid rocker link bracket 100.The hydraulic cylinder 96 is pivotably fixed to frame 92 by rigidcylinder bracket 102 near one end and to a first or lower rocker arm 104of the rocker link 98 near the other end. A clevis-like coupling 108receives the upper rocker arm 106 and forward gauge wheel actuating link110 along a common pivot axis 112. A rear lift wheel link 114 extendstoward the rear of the implement from coupling 108 to rear knuckle 116.The linkage assembly of FIG. 4 functions to simultaneously pivot certainfront and rear wheels between respective retracted and extendedpositions as described earlier in conjunction with FIGS. 1-3.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

What is claimed is:
 1. An agricultural tillage implement, comprising: amain frame section including a plurality of generally downwardlyextending soil working tools, the main frame section adapted to becoupled by a floating hitch arrangement to and towed by a traction unitin a generally horizontal forward direction of travel; a lift wheelpivotably supported with respect to the main frame section at a firstpivot location; a gauge wheel pivotably supported with respect to themain frame section at a second pivot location generally forward of thelift wheel; and a linkage assembly for simultaneously pivoting the gaugeand lift wheels between respective retracted and extended positions forselectively lowering and raising the main frame section and associatedsoil working tools, the linkage assembly including: an actuatorpivotably connected to the main frame section; a rocker link pivotablyconnected to the main frame section having a rocker link first armextending below the main frame section and having a rocker link firstarm lower end coupled to the actuator below the main frame section, anda rocker link second arm extending above the main frame section andhaving a rocker link second arm upper end; a rearwardly extending liftwheel actuating link having a lift wheel actuating link inner end and alift wheel actuating link outer end, wherein the lift wheel actuatinglink inner end is pivotably connected to the rocker link second armupper end above the main frame section and wherein the lift wheelactuating link outer end is arranged toward the lift wheel; and aforwardly extending gauge wheel actuating link having a gauge wheelactuating link inner end and a gauge wheel actuating link outer end,wherein the gauge wheel actuating link inner end is pivotably connectedto the rocker link second arm upper end above the main frame section andwherein the gauge wheel actuating link outer end is arranged toward thegauge wheel, wherein actuation of the actuator moves the rocker linkfirst arm lower end below the main frame section in a first directionand moves the rocker link second arm upper end in a second, opposite,direction to move the inner ends of the lift wheel and gauge wheelactuating links above the main frame section.
 2. The agriculturaltillage implement of claim 1, wherein the actuator is connected to themain frame section rearward of the gauge wheels and forward of therocker link.
 3. The agricultural tillage implement of claim 1, whereinone of the lift wheel actuating link and gauge wheel actuating link isselectively adjustable in length.
 4. The agricultural tillage implementof claim 3, wherein the gauge wheel actuating link is defined by anadjustable length link with two link portions and a turnbuckle couplingthe two link portions together.
 5. The agricultural tillage implement ofclaim 1, wherein the actuator comprises a linear hydraulic actuatoroperable between extended and retracted positions extending rearwardlyfrom the main frame section to the rocker link first arm.
 6. Theagricultural tillage implement of claim 1, wherein the gauge wheelactuating link is pivotably coupled to the gauge wheel by a knucklehaving a first pivot axis positioned relative to the main frame sectionand a second pivot axis displaced from the first axis, and an armextending from the knuckle to the gauge wheel.
 7. The agriculturaltillage implement of claim 1, wherein the lift wheel actuating link andthe gauge wheel actuating link are pivotably connected to the rockerlink second arm along a common pivot axis.
 8. A linkage assembly for usewith an agricultural implement having a frame towed by a traction unitin a generally horizontal forward direction of travel and a front wheeland a rear wheel that are longitudinally spaced from each other relativeto the frame of the agricultural implement, wherein the linkage assemblyis adapted to simultaneously pivot the front and rear wheels betweenrespective retracted and extended positions for selectively lowering andraising the frame and any associated soil working tools, the linkageassembly comprising: an actuator pivotably connected to the frame; arocker link pivotably connected to the frame having a rocker link firstarm extending therefrom and having a rocker link first arm lower endarranged below the frame and coupled to the actuator, and a rocker linksecond arm extending therefrom and having a rocker link second arm upperend arranged above the frame; a rearwardly extending rear wheelactuating link with a rear wheel actuating link inner end and a rearwheel actuating link outer end, wherein the rear wheel actuating linkinner end is pivotably connected to the rocker link second arm upperend; and a forwardly extending front wheel actuating link with a frontwheel actuating link inner end and a front wheel actuating link outerend, wherein the front wheel actuating link inner end is pivotablyconnected to the rocker link second arm upper end, wherein one of therear wheel actuating link and front wheel actuating link is selectivelyadjustable in length, and wherein the front wheel actuating link isdefined by an adjustable length link with two link portions and aturnbuckle coupling the two link portions together.
 9. The linkageassembly of claim 8, wherein the actuator is connected to the framerearward of the front wheel and forward of the rocker link.
 10. Thelinkage assembly of claim 8, wherein the actuator comprises a linearhydraulic actuator extending rearwardly from the frame to the rockerlink first arm, said actuator operable between extended and retractedpositions.
 11. The linkage assembly of claim 8, wherein the front wheelactuating link is pivotably coupled to the front wheel by a knucklehaving a first pivot axis positioned relative to the frame and a secondpivot axis displaced from the first axis, and an arm extending from theknuckle to the front wheel.
 12. The linkage assembly of claim 8, whereinthe front wheel actuating link and the rear wheel actuating link arepivotably connected to the rocker link second arm along a common pivotaxis.